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PR2 / pr2_controllers

The controllers that run in realtime on the PR2 and supporting packages.
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joint trajectory controller should have an optional flag for wraparound joints (ros ticket #3745) #285

Closed ahendrix closed 11 years ago

ahendrix commented 11 years ago

Right now, if you give a command between -pi to pi for the controller, it tends to unwind/wind all the way to these values instead of normalizing going to the closest angle corresponding to these values.

While in some cases, this might actually be the behavior you want, in most cases its not. If a user just wants to go to a normalized angle, he now has to get the current joint angles, figure out which angle corresponds to the correct normalized angle and then send it to the controller. Thus, the user always has to know the current joint angles to be able to send the correct trajectory for joints that wraparound.

A flag to optionally specify that the controller should be using wraparound would be very useful here.

trac data:

ahendrix commented 11 years ago

[sglaser] One possibility is to only wrap to the first point in the trajectory. As in, if the arm is at configuration q, and you send it a trajectory [q1, q2, q3], the controller wraps the elements of q1 so that they are near q, and applies the same offset to q2 and q3.

How does that sound?

ahendrix commented 11 years ago

[sglaser] r35914 in pr2_controllers 1.1.4